Robert Coogan was born Robert Anthony Coogan in Glendale, California, to parents Jack Coogan Sr. and Lillian Coogan. His older brother was Jackie Coogan, perhaps Hollywood's most famous child star of the 1920s. Coogan's only child is Jonathan Coogan. Coogan's nephew is stereographer and 3D Producer Anthony Coogan and his grand-nephew Keith Coogan is also an actor.
Starting as a child actor, Robert Coogan made his film debut as Sooky in Skippy (1931), a comedy-drama family film which was nominated for an Academy Award for Best Picture. He also reprised the role of Sooky in its sequel Sooky (1931). In addition to his appearance in Skippy, Coogan appeared in over one dozen other films and made one appearance in a television production. Coogan continued acting in adulthood, but only with minor success. He also portrayed the role of Humphrey Pennyworth in the Joe Palooka B-movies.
